`SystemPager` buffers output until we’re pretty sure it’s at least a page long, then invokes an external pager and starts streaming output to it. If `close` is called before then, it just prints out the buffered content.
# File lib/pry/pager.rb, line 136 def self.available? if @system_pager.nil? @system_pager = begin pager_executable = default_pager.split(' ').first %xwhich #{pager_executable}` $?.success? rescue false end else @system_pager end end
# File lib/pry/pager.rb, line 125 def self.default_pager pager = ENV["PAGER"] || "" # Default to less, and make sure less is being passed the correct options if pager.strip.empty? or pager =~ /^less\b/ pager = "less -R -F -X" end pager end
# File lib/pry/pager.rb, line 150 def initialize(*) super @tracker = PageTracker.new(height, width) @buffer = "" end
# File lib/pry/pager.rb, line 171 def close if invoked_pager? pager.close else @out.puts @buffer end end
# File lib/pry/pager.rb, line 156 def write(str) if invoked_pager? write_to_pager str else @tracker.record str @buffer << str if @tracker.page? write_to_pager @buffer end end rescue Errno::EPIPE raise StopPaging end